The next day, a medical staff nurse reported that Mangum was hallucinating. Instead of sending him to the hospital, Mangum claims the jailers came into his cell and severely beat him, nearly killing him. The Sevier County Jail documented that jailers thought Mangum was going to walk out of his cell so they stopped him, according to the lawsuit. Mangum's attorneys said the jail's reports didn't indicate that the jailers beat him with objects.

Two days later, Mangum's lawyers said jailers and medical personnel put their client in a wheel chair because he couldn't stand on his own, but they still didn't send him to the hospital. Several hours later, jailers apparently came back to Mangum's cell to find him lying on the floor incoherent. It was then, officials decided to take Mangum to LeConte Medical Center for his injuries, according to the lawsuit.

When he arrived at the hospital, doctors said Mangum was in critical condition and sent him to Fort Sanders Hospital. Mangum's family said for about 10 days, two deputies sat by his bed and wouldn't allow his family to see him. The lawsuit claims Mangum laid in a coma for the next month.

Magnum said he now suffers from brain damage, seizures, neurological disorders, among other ailments.

The lawsuit claims the Federal Bureau of Investigation has launched an investigation into the Sevier County Jail. The FBI also reportedly told Mangum and his family that certain video-taped recordings are missing from the jail, according to court documents.

In 2012, another inmate sued the Sevier County Jail for $225 million. Ronald McDaniel claimed he was paralyzed after he was beaten in the jail in 2011. McDaniel said the jail didn't protect him from the attack and didn't give him proper medical care.